Hi Craig,

I assume the I2C was identical to the old 78C751 devices. I hate it. It runs most the time, but I understand it not completely also.
Most code used from the mouse application note from Philips.

Only the I2C on the P80C552 / P89C668 seems usable.

Nevertheless also on derivates with internal I2C hardware I use always software I2C, if only single master ability was needed.
Its more portable, well proved and less code.
I use still my C or assembler routines from my web.


Peter